Microgravity: A Teacher's Guide With Activities in Science, Mathematics, and Technology

The purpose of this curriculum supplement guide is to define and explain microgravity and show how microgravity can help us learn about the phenomena of our world. The front section of the guide is designed to provide teachers of science, mathematics, and technology at many levels with a foundation in microgravity science and applications. It begins with background information for the teacher on what microgravity is and how it is created. This is followed with information on the domains of microgravity science research; biotechnology, combustion science, fluid physics, fundamental physics, materials science, and microgravity research geared toward exploration. The background section concludes with a history of microgravity research and the expectations microgravity scientists have for research on the International Space Station. Finally, the guide concludes with a suggested reading list, NASA educational resources including electronic resources, and an evaluation questionnaire

Phase-field gradient theory

We propose a phase-field theory for enriched continua. To generalize classical phase-field models, we derive the phase-field gradient theory based on balances of microforces, microtorques, and mass. We focus on materials where second gradients of the phase field describe long-range interactions. By considering a nontrivial interaction inside the body, described by a boundary-edge microtraction, we characterize the existence of a microhypertraction field, a central aspect of this theory. On surfaces, we define the surface microtraction and the surface-couple microtraction emerging from internal surface interactions. We explicitly account for the lack of smoothness along a curve on surfaces enclosing arbitrary parts of the domain. In these rough areas, internal-edge microtractions appear. We begin our theory by characterizing these tractions. Next, in balancing microforces and microtorques, we arrive at the field equations. Subject to thermodynamic constraints, we develop a general set of constitutive relations for a phase-field model where its free-energy density depends on second gradients of the phase field. A priori, the balance equations are general and independent of constitutive equations, where the thermodynamics constrain the constitutive relations through the free-energy imbalance. To exemplify the usefulness of our theory, we generalize two commonly used phase-field equations. We propose a 'generalized Swift-Hohenberg equation'-a second-grade phase-field equation-and its conserved version, the 'generalized phase-field crystal equation'-a conserved second-grade phase-field equation. Furthermore, we derive the configurational fields arising in this theory. We conclude with the presentation of a comprehensive, thermodynamically consistent set of boundary conditions

Extended Larché–Cahn framework for reactive Cahn–Hilliard multicomponent systems

At high temperature and pressure, solid diffusion and chemical reactions between rock minerals lead to phase transformations. Chemical transport during uphill diffusion causes phase separation, that is, spinodal decomposition. Thus, to describe the coarsening kinetics of the exsolution microstructure, we derive a thermodynamically consistent continuum theory for the multicomponent Cahn–Hilliard equations while accounting for multiple chemical reactions and neglecting deformations. Our approach considers multiple balances of microforces augmented by multiple component content balance equations within an extended Larché–Cahn framework. As for the Larché–Cahn framework, we incorporate into the theory the Larché–Cahn derivatives with respect to the phase fields and their gradients. We also explain the implications of the resulting constrained gradients of the phase fields in the form of the gradient energy coefficients. Moreover, we derive a configurational balance that includes all the associated configurational fields in agreement with the Larché–Cahn framework. We study phase separation in a three-component system whose microstructural evolution depends upon the reaction–diffusion interactions and to analyze the underlying configurational fields. This simulation portrays the interleaving between the reaction and diffusion processes and how the configurational tractions drive the motion of interfaces

XR, music and neurodiversity: design and application of new mixed reality technologies that facilitate musical intervention for children with autism spectrum conditions

This thesis, accompanied by the practice outputs,investigates sensory integration, social interaction and creativity through a newly developed VR-musical interface designed exclusively for children with a high-functioning autism spectrum condition (ASC).The results aim to contribute to the limited expanse of literature and research surrounding Virtual Reality (VR) musical interventions and Immersive Virtual Environments (IVEs) designed to support individuals with neurodevelopmental conditions. The author has developed bespoke hardware, software and a new methodology to conduct field investigations. These outputs include a Virtual Immersive Musical Reality Intervention (ViMRI) protocol, a Supplemental Personalised, immersive Musical Experience(SPiME) programme, the Assisted Real-time Three-dimensional Immersive Musical Intervention System’ (ARTIMIS) and a bespoke (and fully configurable) ‘Creative immersive interactive Musical Software’ application (CiiMS). The outputs are each implemented within a series of institutional investigations of 18 autistic child participants. Four groups are evaluated using newly developed virtual assessment and scoring mechanisms devised exclusively from long-established rating scales. Key quantitative indicators from the datasets demonstrate consistent findings and significant improvements for individual preferences (likes), fear reduction efficacy, and social interaction. Six individual case studies present positive qualitative results demonstrating improved decision-making and sensorimotor processing. The preliminary research trials further indicate that using this virtual-reality music technology system and newly developed protocols produces notable improvements for participants with an ASC. More significantly, there is evidence that the supplemental technology facilitates a reduction in psychological anxiety and improvements in dexterity. The virtual music composition and improvisation system presented here require further extensive testing in different spheres for proof of concept

CHARGING OF FINE AEROSOL PARTICLES

CHARGING OF FINE AEROSOL PARTICLE

Metaphor, Objects, and Commodities

This article is a contribution to a symposium that focuses on the ideas of Margaret Jane Radin as a point of departure, and particularly on her analyses of propertization and commodification. While Radin focuses on the harms associated with commodification of the person, relying on Hegel's idea of alienation, we argue that objectification, and in particular objectification of various features of the digital environment, may have important system benefits. We present an extended critique of Radin's analysis, basing the critique in part on Gadamer's argument that meaning and application are interrelated and that meaning changes with application. Central to this interplay is the speculative form of analysis that seeks to fix meaning, contrasted with metaphorical thought that seeks to undermine some fixed meanings and create new meanings through interpretation. The result is that speculative and metaphorical forms are conjoined in an interactive process through which new adaptations emerge. Taking this critique an additional step, we use examples from contemporary intellectual property law discourse to demonstrate how an interactive approach, grounded in metaphor, can yield important insights

Dynamics and Statics of Liquid-Liquid and Gas-Liquid interfaces on Non-Uniform Substrates at the Micron and Sub-Micron Scales

Droplets and bubbles are ubiquitous motifs found in natural and industrial processes. In the absence of significant external forces, liquid-liquid and gas-liquid interfaces form constant mean curvature surfaces that locally minimize the free energy of a given system subject to constraints. However, even for sub-micron bubbles and droplets free of hydrodynamic and hydrostatic stresses (small Capillary, Weber, and Bond numbers), non-equilibrium at the contact line of sessile bubbles and droplets can influence geometries and dynamics. First, the wetting of micron-sized ellipsoidal particles was considered. In the space of axially symmetric interfaces, it is found that multiple constant mean curvature surfaces can satisfy volume and contact angle constraints. Partial encapsulation may be preferred even when the droplet\u27s volume is sufficient to fully engulf the particle. The co-existence of multiple equilibrium states suggests possible hysteretic encapsulation behavior. Secondly, motivated by electron microscopy observations of sub-micron bubbles in a liquid cell, a small mobile and growing bubble confined between two weakly diverging plates is considered theoretically. Scaling analysis suggests that observed bubbles move by continuously wetting and de-wetting the substrates onto which they are adhered. 2D and 3D models are constructed incorporating the Blake-Haynes mechanism, which relates the dynamic contact angle to contact line velocity; partial pinning of the contact line is also considered. In 2D, the system is fully described by a set of non-linear ordinary differential equations that can be readily solved. In 3D, the non-linear PDE system and constraints were solved using a pseudo-spectral method. Both 2D and 3D models predict that in order for a doubly confined bubble to grow in a super-saturated solution it must first increase its curvature; this is in contrast to a free-floating bubble whose curvature always decreases with the addition of mass/volume. Since the surface concentration is proportional to the internal pressure of the bubble, this geometric change temporarily regulates the growth of the bubble. The model predicts growth rates like those observed experimentally that are several orders of magnitude lower than predictions made by classical mass transfer driven growth theory developed by Epstein and Plesset

Angular Momentum Transport in Stellar Interiors

Stars lose a significant amount of angular momentum between birth and death, implying that efficient processes transporting it from the core to the surface are active. Space asteroseismology delivered the interior rotation rates of more than a thousand low- and intermediate-mass stars, revealing that: 1) single stars rotate nearly uniformly during the core hydrogen and core helium burning phases; 2) stellar cores spin up to a factor 10 faster than the envelope during the red giant phase; 3) the angular momentum of the helium-burning core of stars is in agreement with the angular momentum of white dwarfs. Observations reveal a strong decrease of core angular momentum when stars have a convective core. Current theory of angular momentum transport fails to explain this. We propose improving the theory with a data-driven approach, whereby angular momentum prescriptions derived from multi-dimensional (magneto)hydrodynamical simulations and theoretical considerations are continously tested against modern observations. The TESS and PLATO space missions have the potential to derive the interior rotation of large samples of stars, including high-mass and metal-poor stars in binaries and clusters. This will provide the powerful observational constraints needed to improve theory and simulations.Comment: Manuscript submitted to Annual Reviews of Astronomy and Astrophysics for Volume 57. This is the authors' submitted version. Revisions and the final version will only become available from https://www.annualreviews.org/journal/astr